TASK22224: fix downloadblob path normalization for prefixed blob names

pages/api/file/downloadblob.js

@@ -49,17 +49,24 @@ ApiProxy.get(async (req, res) => {
     }
 
     try {
-        const bloblocation =
+        const decodedBlobName = decodeURI(blobName);
-            casefolderID + (blobName.indexOf(".json") > 0 ? "/" : "/files/");
+        const normalizedBlobName = decodedBlobName.startsWith(
+            casefolderID + "/"
+        )
+            ? decodedBlobName
+            : casefolderID +
+              (decodedBlobName.indexOf(".json") > 0 ? "/" : "/files/") +
+              decodedBlobName;
 
         const downloaded = await downloadFile(
             containerName,
-            bloblocation + decodeURI(blobName)
+            normalizedBlobName
         );
+        const responseFileName = decodedBlobName.split("/").pop();
 
         res.setHeader(
             "content-disposition",
-            "attachment; filename=" + decodeURI(blobName)
+            "attachment; filename=" + responseFileName
         );
         return res.status(200).send(downloaded);
     } catch (error) {